Pollen tubes of prk6, prk3 prk6, prk3 prk6 prk8-2 and prk1 prk3 prk6 mutants were assessed in this assay. Full-length PRK6, the PRK6 orthologue of C. rubella (CrPRK6), kinase-domain-deleted PRK6 (K-del), and cytosolic-domain-deleted PRK6 (cyto-del-2) were expressed as mRuby2 fusion proteins under the control of their own promoters. Upper differential interference contrast images show semi-in-vivo pollen tube growth in the medium containing the AtLURE1 peptide at 6 HAP. Yellow arrowheads mark some of the pollen tubes showing apparent wavy phenotype. The bottom two images are a blight field image and a confocal image for mRuby2 of a representative pollen tube in the wavy assay. The data are representative images of at least three assays for one or two lines of each genotype. Scale bars, 200 μm (top) and 20 μm (bottom).